cooling

I have tried that when I was working in the attic, just pointed it at a gable vent.  I wouldn't do it when I wasn't up there, as I don't think those fans were made to work in that kind of extremely hot environment...would be a potential fire hazard.

A decent purpose built electric gable fan is only $50 or so, plus whatever the electrician might charge to run the wiring.  Well worth the safety.

Believe it or not we just discovered that we have a working attic fan on the gable end of the house. I knew it was there and thought it was just a vent. Lo and behold a friend said are you sure that's not an attic fan up there? So we went up and looked properly. Turns out it's all wired up with a thermostat and everything LOL.
 
We've been here 18 months and hadn't paid much attention to the attic, only opening the hatch to store stuff up there within reach really. The switch is right next to the light switch too. I'm mad now that we went all summer last year not using it! It's been going great guns since we discovered it.
 
We only found it four days ago and I'm not happy with leaving the thing on overnight when we're sleeping ( don't know if you can leave them on 24/7?) until we get it checked by an electrician for safety although it looks fine, no loose wires or anything. We're turning it on in the morning when we get up and putting it off at bedtime. Finally my AC is cutting out every so often instead of running constantly. Fingers crossed it keeps going because you can definitely feel the difference.